Fuel economy for new cars, SUVs, vans, and pickup trucks sold last month in the United States reached 24.5 miles per gallon, an all-time high since researchers began gathering the data in 2007.

The University of Michigan Transportation Research Institute, which publishes the data monthly, has seen the average fuel economy (measured by the window sticker ratings) of new light-duty vehicles sold gradually rise since 2007:

"The recent improvement reflects the improved fuel economy of the 2013 model year vehicles," University of Michigan researcher Brandon Schoettle said in a news release.

That's a good sign not only for sustainability, but also for automakers that are working at making cars more fuel efficient to meet the Obama administration's ambitious average fuel economy requirement of 54.5 mpg for all new cars and light trucks by 2025.